When do cats fly?
 

I have a 24' Active Thunder Cat powered by twin Merc ProMax 300's. As some of you know in this forum I am in the process of detuning this raceboat to be a bit more appealing to the wife. Throttle-up is setting me up with the right props but I need to know more about tunnel hulls and cats. At what speed does the tunnel take effect and raise the hull up? How does this change handling? At what speed does this become dangerous? (no tabs). How far can I push this in calmer water?(very important question). Yea when the urge hits I would like to max the throttles. I plan to run this boat in the bays of FL and Mobile Bay AL. Chop will be 2' or less (hopefully). When its a nice day I will go out in the gulf at a speed that wont scare the wife. But when the water is nice in the bay I want to drop off the wife and rip! Top end is not that important to me as this boat as currently set up can go way faster than my ability to handle it.

I am not some stupid rich kid that doesnt know boats. I am a 49 year old experimental test pilot that has owned and loved boats forever. I am now in a position to obtain that dream boat - and have - but need to tame it to my ability but leave that back door to speed open - I may open it someday.

Thanks....TJ

Re: When do cats fly?
 

How fast does it go?

Re: When do cats fly?
 

on calm water, you will "feel" it take set and just start riding on rails... the speed will be different in every boat... mine really takes a nice set at about 80 and just glides from there up over 100.... just take it easy and do it in steps, you will be riding the rev limiters with those rworked props in no time and putting the bigger wheels back on....

Re: When do cats fly?
 

TJ when cats first became popular everybody was concerned about blowovers. Well as it turns out stuffing was a much bigger problem. This is not to say you can not have a blowover but a little restraint with the trim switch will help. Stuffs usually happen in rough water. Go at your own comfort level without passengers and you will feel the limits of your hull.

Re: When do cats fly?
 

Yea I gotta take it slow. The boat as currenly set up will do 110. This is an insane speed for me right now. 90 is good - when I push those golden levers forward I want to feel it like I did with the jets.

Re: When do cats fly?
 

Sean --- you do over 100?

Re: When do cats fly?
 

tj309,49 huh!I believe that's the sigh of a GOOD test pilot.Have fun with the new boat.You'll know what to do.BOB

Re: When do cats fly?
 

mmwalters - your advice is always the best. trim is very important. I think when I get the new props and maybe have to lower the motors things will be great.

Re: When do cats fly?
 

Well I am still alive and maybe you know the old saying - there are no old bold pilots ....

Re: When do cats fly?
 

Let the big head do the thinking when you are chosing your water, don't over trim, slow down if it just doesn't feel right, and have fun.

Re: When do cats fly?
 

Bob you are right. I can feel what is right or not. I wont blow the cat over because I will feel that happening hopefully well before that happens.

Re: When do cats fly?
 

2 members of this forum have told me restraint on the trim switch. I do not know exactly what this means?

Re: When do cats fly?
 

The higher you hang the trim, the looser the boat will run. As with anything in life, too much is always jut that....TOO MUCH. Conservative trim angles will keep the bow lower and help the boat take off, fly and more importantly land level. It will also reduce your chance of a blow over. You commented that you will know its coming long before it does.....probably not. Blow overs happen in an instant. Also important to your safety is learning the hulls cornering characteristics before finding out the hard way where and when it wants to spin out. Start easy and if you feel the outside sponson nosing in on a corner, ease up on the wheel, NEVER the sticks as this will amplify the problem and you will probably end up swimming. You will find that cats tend to "slide" thru corners at speed but dig and turn real hard at slower speeds.
As to your initial question, my daytona starts to "fly" at around 70 mph and really takes a set at 80.

Re: When do cats fly?
 

I agree with what Airpacker said completely. You cannot rely on "feeling" a blowover coming as it would be too late for you to do anything significant by the time you "felt it" coming. If you are flying along at 100 and hit a small wave that upsets your boats attitude you can find yourself upside down in a fraction of a second.

To illustrate the trim, on one of my boats you can have the trim tucked in slightly (as you would to take off) and go full throttle. The boat will max out in the mid 70's. Once you start to trim up the engine, and the boat begins to pack air, the speed will steadily increase to about 90 where this boat reaches it's top end with current power. You can feel the boat getting lighter and smoother on the water. You do not want to go too far with the trimming though.

Take it one step at a time and maintain your comfort level.

Re: When do cats fly?
 

It means you don't want to trim it like a V hull, let the tunnel work for you. You don't want to be facing the sky when you are running full throttle and hit a large wake. You want to feel the stearing but not feel heavy in the nose. I doubt you would have a blow over problem at 110 if it's trimmed right. Only my opinion.

Re: When do cats fly?
 

Watch your tack and speedo you will find the sweet spot where it really picks up speed around 75 to 80 in my old ChrisCat trim it up intill it gets loose then drop back on the trim to keep it flying level. Hyd jack plates will give you the best of both worlds with clamp ons. I put one on a boat I had and loved it great take off top end and ability to rooster tail all in one.

Re: When do cats fly?
 

the cat MUST fly! you are riding skimming stone , thrust maintains your momentum. I feel a slight bow up attitude achieved by correct cg.(about 1/3 forward of the transom ) is essential . In many cat racing miles i never had to trim up or down more than one click .Trim tabs and trim adjustments generally compensate for deficiencies in set up. (drive height , balance etc. ). your vessel should start to air out at about 40-50 , and, as you increase speed feel lighter and smoother , on rails , especially in a small chop . i'm pretty sure actives were good running safe boats. keep your eyes on the road and enjoy the "flight".

Re: When do cats fly?
 

My 39 airs out @ 70 mph.

Lots of good advice in a few posts. Common sense is the key. Speed in a cat is fun but this is one machine where alcohol (even by passengers), speed, boat traffic and gasoline should not be mixed.

Re: When do cats fly?
 

generally after you stick a light m80 under em......

Re: When do cats fly?
 

I thought it was when you kicked them in the azz. :evilb:

Re: When do cats fly?
 

TJ -

Providing you are in VFR weather, let her rip, even if it gets airborne, you're still rated and current aren't you?

Just kidding!!

Nice to see someone asking the right questions and doing the right thing by not just going out and becoming a statistic!!!

Take your time, have fun and be safe!!!

Re: When do cats fly?
 

Great advice. Do you have a tunnel tab on the boat? If so, use the same logic Airpacker has noted above: Conservative use!!!!!! Several cat owners NOT knowing or just simply forgeting to to bring the tab up have stuffed or barrel rolled their cat with improper use.

Re: When do cats fly?
 

There is no tab on the boat. I just got 2 new Hyromotive Q-IV's at 29.5" which will be tried out Sunday. Cant wait. It's interesting what Matt & Julie at Throttle-Up did for me - They took props designed for a Bravo-1 and re-worked them for my 300 ProMax's. Reason - better transom lift. This should help my hole shot and allow me to get on plane faster and at a slower speed.

Thanks for all the insight - this forum has been a goldmine of knowledge and good advice.....TJ